CAIRO (AP) — Embattled Egyptian President Mohammed Morsi’s defiance of an ultimatum from the military shows that he and his Islamist Muslim Brotherhood are prepared to run the risk of challenging the army.

He vowed not to resign late Tuesday, hours before a deadline to yield to the demands of millions of protesters or see the military suspend the constitution, disband parliament and install a new leadership.

The Islamist leader says he rejects all “dictates” — from home or abroad. Outside on the streets, the sense that both sides are ready to fight to the end sharpened, with clashes between his supporters and opponents that left at least 23 dead, most of them in a single incident of fighting outside Cairo University.

Morsi, who a year ago was inaugurated as Egypt’s first freely elected president, pledged to protect his “constitutional legitimacy” with his life.